Astronomy and Astrophysics – Astrophysics
Scientific paper
2003-12-09
Astrophys.J. 604 (2004) 108-115
Astronomy and Astrophysics
Astrophysics
22 pages, 6 figures, ApJ, in press (v2:Corrected typos.)
Scientific paper
10.1086/381744
We investigate the evolution and number distribution of radio halos in galaxy clusters. Without re-acceleration or regeneration, the relativistic electrons responsible for the diffuse radio emission will lose their energy via inverse-Compton and synchrotron losses in a rather short time, and radio halos will have lifetimes $\sim$ 0.1 Gyr. Radio halos could last for $\sim$ Gyr if a significant level of re-acceleration is involved. The lifetimes of radio halos would be comparable with the cosmological time if the radio-emitting electrons are mainly the secondary electrons generated by pion decay following proton-proton collisions between cosmic-ray protons and the thermal intra-cluster medium within the galaxy clusters. Adopting both observational and theoretical constraints for the formation of radio halos, we calculate the formation rates and the comoving number density of radio halos in the hierarchical clustering scheme. Comparing with observations, we find that the lifetimes of radio halos are $\sim$ Gyr. Our results indicate that a significant level of re-acceleration is necessary for the observed radio halos and the secondary electrons may not be a dominant origin for radio halos.
Huen Ip Wing
Hwang Chorng-Yuan
Kuo Ping-Hung
No associations
LandOfFree
The Evolution of Diffuse Radio Sources in Galaxy Clusters does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The Evolution of Diffuse Radio Sources in Galaxy Clusters, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Evolution of Diffuse Radio Sources in Galaxy Clusters will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-40880